Try to generate Column2D chart on the following data:
<chart decimals="0" />
<set label='A' value='1' />
<set label='B' value='1' />
<set label='C' value='1' />
</chart>
you will get the following result:
Note, that Y axis' labels go as 0, 0, 1, 1, 1...
P.S. The software that runs the forum doesn't let me to post xml, even within |code| |/code| tags. I had to use a screen shot instead.